滇中冷凉山区不同播期反季花椰菜产量效益分析

为摸索滇中高海拔冷凉山区反季节栽培花椰菜的最佳播期以集成高效栽培技术推广应用,于2017—2018年选择海拔2250 m的云南省峨山县塔甸镇大西村地块进行9个播期的2年随机区组试验。结果表明,花椰菜生育期随播期推迟而延长,而花球采收期除播期7月10日外随播期推迟而逐渐增长;花椰菜株高、外叶数、开展度、球高、球径和单球重等农艺性状有随播期延迟呈现先逐渐减小而后又逐渐增大的趋势;莲座期黑腐病和霜霉病的病情指数随着播期的延迟呈现先逐渐升高而后又逐渐下降的趋势;花椰菜小区产量随着播期的延迟呈现先逐渐下降而后又逐渐提高的趋势,播期4月20日和4月30日与其余7个播期产量之间的差异达极显著水平。综合花椰菜在冷凉山区反季节栽培的生产实际和各播期产量产值及商品性表现,推荐滇中高海拔冷凉山区反季节栽培花椰菜的最佳播期为4月20—30日。     

油菜黑胫病菌T-DNA插入诱变因素优化及突变体筛选

油菜黑胫病是由Leptosphaeria biglobosa引起的一种真菌病害。这种病害在我国油菜产区广泛发生，并造成一定的经济损失。为通过获取突变体来研究L. biglobosa的生态适应性机制及致病机制，本文优化了影响农杆菌介导转化（ATMT）油菜黑胫病菌L. biglobosa菌株Lb731的因素，评估转化子质量，并筛选相关突变体。结果明确了农杆菌介导转化菌株Lb731的最佳因素：潮霉素B浓度为50 μg/mL，转化受体（分生孢子）培养时间为15 d (20℃)，浓度为2 × 10^7~8孢子/mL，农杆菌-受体共培养温度为25℃，共培养时间为72 h。在最适条件下的转化效率达到80个转化子/百万分生孢子。T-DNA插入基因组的频率为100%，单拷贝插入频率为72.7%，转化子抗潮霉素性状能稳定遗传。从2136个转化子中获得了11个菌丝生长减缓突变体，7个色素产生缺陷突变体和14个分生孢子产生缺陷突变体，并从这些突变体中鉴定出7个致病力丧失突变体。采用hiTAIL-PCR技术，从3个突变体中获得了T-DNA插入位点侧翼序列。上述结果为深入研究L. biglobosa的生态适应性机制及致病机制提供了材料和线索。     

台盼蓝活体染色法观察瓦氏黄颡鱼血脾屏障研究

为探讨瓦氏黄颡鱼(Pelteobagrus vachelli)脾脏组织结构和血脾屏障位置,该研究对其脾脏进行了形态大小、组织学和活体染色观察。结果显示,瓦氏黄颡鱼的脾脏位于腹腔中部,呈暗红色,脾体指数为0.120%~0.273%;对健康脾脏制备石蜡切片,分别进行HE染色和改良James染色,显微镜观察发现其脾组织主要由不发达的被膜系统、分界不清的红髓和白髓及由网状纤维和胶原纤维组成的纤维支架构成。其中网状纤维主要位于脾索和椭球体周围,胶原纤维主要位于脾索;使用台盼蓝活体染色法对健康瓦氏黄颡鱼的血脾屏障部位和功能探索发现,台盼蓝主要位于脾脏的椭球体内皮细胞中,最早出现在注射后的第4小时,随时间推移在椭球体内逐渐累积,24 h后数量显著增加,并持续增加至第72小时。结果表明椭球体内皮细胞是血脾屏障的重要组成成分。     

鸡Ii结合Rab5a和Rab7b分子的分析

本研究旨在探明鸡恒定链（invariant chain，Ii）与内吞体转运蛋白Rab5a和Rab7b结合的结构域和在细胞内共定位的特征。首先，用PCR和基因突变技术将Ii胞浆区与跨膜区[Ii_{（Cyt-Tra）}]、Ii CLIP （class Ⅱ-associated invariant chain peptide）-三聚体区[Ii_{（CLIP-TRIM）}]和Ii突变体[Ii_{（M81-87aa）}、Ii_{（M91-99aa）}和Ii_{（M81-99aa）}]分别插入pET-32a和pEGFP-C1构建相应的原核和真核重组质粒。其次，将构建的含有绿色荧光蛋白的重组质粒与实验室保存的含有红色荧光Rab5a和Rab7b的重组质粒共转染至人胚胎肾细胞系293 T，观察它们的共定位。将构建的原核重组质粒进行表达和纯化，最后用拉下法和免疫印迹检测Ii与Rab5a和Rab7b的结合域。结果表明，成功构建Ii结构域及Ii突变体的重组质粒。Ii_{（Cyt-Tra）}及Ii突变体均能与Rab5a和Rab7b在细胞内共定位，而Ii_{（CLIP-TRIM）}与空载体却不能。Ii的胞浆区和跨膜区是与Rab5a和Rab7b结合的功能结构域，而不是CLIP与三聚体区。综上所述，鸡Ii与Rab5a和Rab7b共定位和结合的区域是其胞浆区和跨膜区，而不是内质网腔区。这些结果提示Rab分子参与了Ii在胞内细胞器的转运机制，为进一步研究Ii及其载体在细胞内的转运机制和功能提供了新的途径。     

甘露糖修饰的壳聚糖聚乳酸-羟基乙酸共聚物纳米微球作为口蹄疫病毒核酸疫苗递送载体的特性评价

旨在对制备的甘露糖修饰的壳聚糖聚乳酸-羟基乙酸共聚物[poly （D，L-lactide-co-glycolide），PLGA]纳米微球作为口蹄疫病毒（foot-and-mouth disease virus，FMDV）核酸疫苗递送载体进行评价。采用西佛碱反应和元素分析制备具有一定取代度的甘露糖修饰的壳聚糖衍生物（mannose modified chitosan，MCS），然后，经双重乳化挥发法制备得到甘露糖修饰的壳聚糖PLGA纳米微球（MCS-PLGA-NPs）。采用纳米粒径仪检测MCS-PLGA-NPs粒径分布和表面电势（zeta）、扫描电镜考察其形态、琼脂糖凝胶电泳观察其对质粒的吸附和吸附质粒后抵抗核酸酶降解能力、CCK-8法检测MCS-PLGA-NPs的细胞毒性、激光共聚焦观察巨噬细胞对MCS-PLGA-NPs-质粒DNA复合物的摄取、荧光显微镜和Western blot验证MCS-PLGA-NPs加载质粒DNA在细胞中的表达。元素分析结果表明，成功制备了取代度为5%~10%的MCS。纳米粒径测定和扫描电镜结果表明，MCS-PLGA-NPs的zeta为正值、粒径分布均匀且形态规则呈球形。琼脂糖凝胶电泳结果显示，MCS-PLGA-NPs吸附质粒的能力随着其质量的增加而增强并且可以在一定程度上抵抗核酸酶降解质粒DNA。在细胞毒性试验中，不同浓度的MCS-PLGA-NPs与RAW264.7细胞共孵育24 h后，细胞存活率仍在85%以上。在细胞摄取试验中，用激光共聚焦显微镜可以明显观察到质粒DNA结合到纳米微球表面被RAW264.7细胞摄取。荧光显微镜和Western blot试验证明MCS-PLGA-NPs加载质粒DNA可以在细胞中进行表达。综上表明，本研究成功制备了MCS以及具有递送核酸疫苗能力的MCS-PLGA-NPs，为FMDV核酸疫苗的递送研究提供了新的方向和见解，也为该递送载体携带特定抗原靶向抗原递呈细胞表面甘露糖受体以及应用于动物免疫的研究奠定基础。     

The priority of management factors for reducing the yield gap of summer maize in the north of Huang-Huai-Hai region,China

Understanding yield potential, yield gap and the priority of management factors for reducing the yield gap in current intensive maize production is essential for meeting future food demand with the limited resources. In this study, we conducted field experiments using different planting modes, which were basic productivity(CK), farmer practice(FP), high yield and high efficiency(HH), and super high yield(SH), to estimate the yield gap. Different factorial experiments(fertilizer, planting density, hybrids, and irrigation) were also conducted to evaluate the priority of individual management factors for reducing the yield gap between the different planting modes. We found significant differences between the maize yields of different planting modes. The treatments of CK, FP, HH, and SH achieved 54.26, 58.76, 65.77, and 71.99% of the yield potential, respectively. The yield gaps between three pairs: CK and FP, FP and HH, and HH and SH, were 0.76, 1.23 and 0.85 t ha~(–1), respectively. By further analyzing the priority of management factors for reducing the yield gap between FP and HH, as well as HH and SH, we found that the priorities of the management factors(contribution rates) were plant density(13.29%)fertilizer(11.95%)hybrids(8.19%)irrigation(4%) for FP to HH, and hybrids(8.94%)plant density(4.84%)fertilizer(1.91%) for HH to SH. Therefore, increasing the planting density of FP was the key factor for decreasing the yield gap between FP and HH, while choosing hybrids with density and lodging tolerance was the key factor for decreasing the yield gap between HH and SH.     

Regional distribution of wheat yield and chemical fertilizer requirements in China

Quantification of currently attainable yield and fertilizer requirements can provide detailed information for assessing the food supply capacity and offer data support for agricultural decision-making. Datasets from a total of 5 408 field experiments were collected from 2000 to 2015 across the major wheat production regions in China to analyze the spatial distribution of wheat yield, the soil nutrient supply capacity(represented by relative yield, defined as the ratio of the yield under the omission of one of nitrogen(N), phosphorus(P) and potassium(K) to the yield under the full NPK fertilizer application), and N, P and K fertilizer requirements by combining the kriging interpolation method with the Nutrient Expert Decision Support System for Wheat. The results indicated that the average attainable yield was 6.4 t ha~(-1), with a coefficient of variation(CV) of 24.9% across all sites. The yields in North-central China(NCC) and the northern part of the Middle and Lower reaches of the Yangtze River(MLYR) were generally higher than 7 t ha~(-1), whereas the yields in Southwest China(SWC), Northeast China(NEC), and the eastern part of Northwest China(NWC) were usually less than 6 t ha~(-1). The precentage of area having a relative yield above 0.70, 0.85, and 0.85 for N, P, and K fertilizers accounted for 52.3, 74.7, and 95.9%, respectively. Variation existed in N, P, and K fertilizer requirements, with a CV of 24.8, 23.9, and 29.9%, respectively, across all sites. More fertilizer was needed in NCC and the northern part of the MLYR than in other regions. The average fertilizer requirement was 162, 72, and 57 kg ha~(-1) for N, P_2O_5, and K_2O fertilizers, respectively, across all sites. The incorporation of the spatial variation of attainable yield and fertilizer requirements into wheat production practices would benefit sustainable wheat production and environmental safety.     

偏高岭土对高强机制砂混凝土性能的影响

利用扫描电子显微镜(SEM)、压汞法(MIP)、快速氯离子迁移系数法(RCM)等手段,研究了偏高岭土(MK)掺量对高强机制砂混凝土抗压强度以及抗氯离子渗透性能的影响.研究发现: 掺入MK能够有效改善高强机制砂混凝土的力学性能和抗氯离子渗透性能:随MK掺量增加,抗压强度与抗氯离子渗透性能均呈先增大后减小的趋势,最佳MK掺量为8%,此时28 d抗压强度为98.5 MPa,较基准组增加13%,氯离子迁移系数为1.89×10^-12 m²/s,较基准组减小60%.微观结构试验表明适宜的偏高岭土掺量能够有效促进水泥水化;偏高岭土颗粒的晶核效应和微集料填充效应协同作用,使得机制砂混凝土的微观结构更加均匀密实,机制砂混凝土的多害孔、有害孔减少,少害孔增加,从而提高了机制砂混凝土抗压强度和抗氯离子渗透性能.     

早熟玉米杂交组合主要农艺性状与产量的灰色关联度分析

应用灰色关联度分析法,对19个玉米杂交组合性状进行分析。结果表明,各性状与产量的关联度大小依次为:株高>生育期>倒折率>穗行>行粒>秃尖>含水量>百粒重>穗位高>倒伏率>穗长>出籽率>穗粗。在育种工作中应该注重对株高、生育期和倒折率的选择,同时要结合不同性状间相互关系的综合表现进行育种,使玉米产量有较大提升。     

根系修剪对枳生长及相关基因表达的影响

以枳实生苗为试验材料,通过两年重复试验分析了不切除主根、切除1/3主根、切除1/2主根、切除2/3主根等4个不同水平根系修剪处理下枳实生苗生长发育、根系构型和营养吸收的情况,并检测了不同水平根系修剪处理对侧根发育关键基因表达量的影响。结果表明,切除1/2主根处理增加了枳实生苗的株高、茎粗、地上部鲜重和根系鲜重,改善了根系构型参数(侧根数、总根长、根表面积和平均长度),增加了根系P、K、Ca、B、Fe、Na和Zn等营养元素含量。另外,实时荧光定量PCR(qRT-PCR)检测发现,根系修剪处理诱导了侧根发育关键基因HOX1和CYP2的积累,并抑制了IAA11和IAA13的表达。综上所述,适度根系修剪可能通过诱导HOX1、CYP2基因的上调和IAA11、IAA13基因的下调来调控枳实生苗侧根的生长发育,改善根系构型,从而提高枳实生苗对营养元素的吸收能力及植株的生长发育。